The Science and Politics of Global Climate Change:
A Guide to the Debate

Andrew E. Dessler + Edward A. Parson

After an outline in chapter one, chapter two of The Science and Politics
of Global Climate Change considers some general, philosophical issues.
It explains the difference between positive and normative statements and
then offers introductions to science, to politics and policy making, and
to their interaction and the role of scientific assessments. This is
a clearly-written and balanced account, acknowledging the distinctive
features of both science and the political process, but allowing neither
to separate itself from connections to and dependencies on the other,
or the rest of the human world.

Chapter three is a summary of the current state of scientific knowledge
about climate change, focusing on temperatures. It considers questions
such as "are temperatures rising and how do we measure them?", "are human
activities responsible for global warming?", "what are the expected
changes over the next century?" and "what are the likely effects of
these?". In forty pages this is obviously only a summary, but it is a
solid presentation: the most recent (2007) IPCC report wasn't available,
but much of the work it drew on is used.

Chapter four considers possible policy responses to global warming.
Adaptation will be a key part of response to climate change, but
"mitigation" measures, to reduce emissions of carbon dioxide and other
greenhouse gases, will also be essential. Models here depend on emission
trends, economic growth, and technological progress. Key policy tools,
available at national and international levels, include carbon taxes
and cap-and-trade permit systems. (A brief appendix presents some basic
economics, looking at discounting, marginal costs, and permit trading.)
Any such systems need to carefully constructed and timed so as to provide
the right incentives, both for individual states and for businesses.

Putting it all together in some kind of cost-benefit analysis or
"integrated assessment" is difficult and involves major uncertainties:

"alternative plausible specifications can increase the optimal
reduction in twentyfirst-century emissions from less than 10
percent to more than 80 percent".

Geoengineering possibilities are briefly touched on.

Chapter five considers aspects of the current "impasse". Dessler and
Parson describe the lack of progress on international policy and some of
the criticisms of the Kyoto Protocol. Turning to the science, they write:

"It is not possible to address all the erroneous and misleading
claims advanced in the climate-policy debate. They are too
numerous, and they are also a moving target."

But they tackle some of the less patently false arguments of the
"skeptics", about the reality of warming, its cause, and its likely
magnitude. More generally, they consider policy skepticism in the face
of uncertainty, sound science, and the status of IPCC reports.

Dessler and Parson conclude with some recommendations of their own:
they argue for attempting to keep warming below 3 degrees Celsius and
atmospheric carbon dioxide below 450ppm, and recommend a "tradable
emission permit system including an escape valve". As possible
alternatives to sticking with or reforming the Kyoto Protocol, they
suggest a bilateral agreement between China and the United States, or a
"coalition of the willing" of committed developed nations, with trade
levies to prevent global disincentives.

The Science and Politics of Global Climate Change is an excellent
overview of the topic, suitable for lay readers but potentially also
policy-makers and scientists seeking a broader perspective. For those
who want more, each chapter has annotated further reading recommendations.
It is unfortunately in the wrong format to reach a really broad audience:
it is a paperback, but it's a quarto with a recommended retail price
of US$40. It would have been a good candidate for Cambridge University
Press' sadly discontinued Canto series. In any event, every general
library should have a copy.